Project

# Title Team Members TA Documents Sponsor
66 A New Approach to an External Ventricular Drain (Capstone Project)
 David Kapelyan
Isiah Lashley
Ralph Nathan
 Jason Jung design_document1.pdf
final_paper1.pdf
grading_sheet1.pdf
proposal1.pdf
video
Team Members:
- Ralph Nathan (ralphn2)
- David Kapelyan (davidik2)
- Isiah Lashley (ilashl2)

# Problem
External Ventricular Drains (EVDs) are used to drain cerebrospinal fluid (CSF), but if done incorrectly, they can cause severe damage, including death. To ensure the correct amount of CSF is drained, the pressure transducers on the EVD must be properly zeroed. However, patients often move during sleep or daily activities such as showering, which can lead to incorrect pressure readings and improper CSF drainage. According to Dr. Suguna Pappu, there have been numerous cases where approximately 40 ccs of CSF were drained instead of the intended 10 due to zeroing errors. This, again, can result in significant harm or even death.
In summary, a new approach to EVDs is necessary, one that provides stable pressure readings even when the patient is in motion. This capstone project aims to create advancements in EVDs.
# Solution
We plan to utilize an STM32 microcontroller to process input from a pressure transducer connected to the catheter through which cerebrospinal fluid (CSF) is drained from the brain. Our design will incorporate a pipe tee in series with a two-way solenoid valve. The catheter extending from the skull will be connected to the tee, which will also be fitted with a pressure gauge. This pressure gauge will be linked to the microcontroller, which will control whether the solenoid valve is open or closed. Measuring pressure digitally, rather than using a manometer, will eliminate the issue of set-point shifts caused by patient movement. Additionally, there will be no need to manually set a “zero” point, as this can be calibrated in software.
We will use an instrumentation amplifier with a shunt resistor to buffer signals from the pressure transducer, ensuring accurate readings by the microcontroller. Digital signal processing (DSP) will then be performed via the microcontroller, including noise filtering, adaptive thresholding for real-time pressure management, and data logging of pressure readings. The system will regulate the flow of CSF to a drain collection bag via a push-connected solenoid valve. The microcontroller will communicate with a display or bedside monitor via Bluetooth, presenting pressure data—including real-time pressure graphs, an alarm system for abnormal pressure readings, and data logs for physician review—through a graphical user interface (GUI). Additionally, we will implement fail-safes to prevent over-drainage or blockage and include a manual override in case of system failure.



# Solution Components

## STM32 Microcontroller
An STM32 microcontroller with an on-package RF transceiver that supports Bluetooth will be utilized. The ADC of the controller supports a resolution of 12 bits which will be useful for accurately measuring the output signal of our pressure gauge. The STM32 Microcontroller comes with an internal reference voltage that is typically derived from the supply voltage.


## Power System Circuit
A high-voltage rail powered by an AC-DC wall adapter will be used to power the board. A linear regulator will be utilized to decrease the voltage such that it can be used to power the microcontroller.

## Push Connect Solenoid Valve For Drainage
A switch will be placed between the high-voltage rail and the solenoid input. The switch will be controlled by an output signal from the microcontroller.

## Pressure Transducer
The pressure transducer will be connected to the pipe tee. The pressure transducer will need to be a precision pressure transducer as the standard Intracranial Pressure is approximately 16mg(0.309 PSI) which is a relatively low pressure. The transducer will have a current output which will be connected to a shunt resistor across which the voltage will be measured using an instrumentation amplifier.

# Criterion For Success

A successful project will result in a device that accurately reads and processes pressure data from a transducer with minimal noise and high precision. The system must effectively regulate cerebrospinal fluid (CSF) drainage by dynamically controlling a solenoid valve to maintain an average outflow of 10cc/hour, preventing over-drainage or blockage. Additionally, the microcontroller must wirelessly transmit real-time pressure readings via Bluetooth to a bedside monitor, where a graphical user interface (GUI) will display real-time pressure graphs, generate alarm notifications for abnormal pressure levels, and log data for physician review. To ensure safety and reliability, the system must incorporate fail-safes to prevent malfunctions and provide a manual override for emergency control. By meeting these criteria, the project will achieve its goal of delivering an automated, accurate, and user-friendly solution for CSF drainage management.

# Parts:
STM32
PCB
Push Connect Solenoid Valve
Pipe Tee
Pressure Transducer
Instrumentation Amplifier

Links:

¼” push connect solenoid valve
⅛” npt solenoid valve

https://www.omega.com/en-us/pressure-measurement/pressure-transducers/px119/p/PX119-015GI

https://www.coleparmer.com/i/cole-parmer-0-25-accuracy-transmitter-0-to-2-psi-4-to-20-ma-output/6807503

https://www.mouser.com/ProductDetail/Analog-Devices/ADR435BRZ?qs=WIvQP4zGanhj7%2FQWeFYslw%3D%3D&utm_id=22030944703&gad_source=1&gclid=CjwKCAiAtYy9BhBcEiwANWQQLyuDFchHNWjCoLscoWoVpM2fdflY2CcCi-fQ9bxPrEm5EPQFvoIeNxoCPqgQAvD_BwE

Bracelet Aid for deaf people/hard of hearing

Aarushi Biswas, Yash Gupta, Anit Kapoor

Bracelet Aid for deaf people/hard of hearing

Featured Project

# PROJECT TITLE: Bracelet Aid for deaf people/hard of hearing

# TEAM MEMBERS:

- Aarushi Biswas (abiswas7)

- Anit Kapoor (anityak3)

- Yash Gupta (yashg3)

# PROBLEM

We are constantly hearing sounds around us that notify us of events occurring, such as doorbells, fire alarms, phone calls, alarms, or vehicle horns. These sounds are not enough to catch the attention of a d/Deaf person and sometimes can be serious (emergency/fire alarms) and would require the instant attention of the person. In addition, there are several other small sounds produced by devices in our everyday lives such as washing machines, stoves, microwaves, ovens, etc. that cannot be identified by d/Deaf people unless they are observing these machines constantly.

Many people in the d/Deaf community combat some of these problems such as the doorbell by installing devices that will cause the light in a room to flicker. However, these devices are generally not installed in all rooms and will also obviously not be able to notify people if they are asleep. Another common solution is purchasing devices like smartwatches that can interact with their mobile phones to notify them of their surroundings, however, these smartwatches are usually expensive, do not fulfill all their needs, and require nightly charging cycles that diminish their usefulness in the face of the aforementioned issues.

# SOLUTION

A low-cost bracelet aid with the ability to convert sounds into haptic feedback in the form of vibrations will be able to give d/Deaf people the independence of recognizing notification sounds around them. The bracelet will recognize some of these sounds and create different vibration patterns to catch the attention of the wearer as well as inform them of the cause of the notification. Additionally, there will be a visual component to the bracelet in the form of an OLED display which will provide visual cues in the form of emojis. The bracelet will also have buttons for the purpose of stopping the vibration and showing the battery on the OLED.

For instance, when the doorbell rings, the bracelet will pick up the doorbell sound after filtering out any other unnecessary background noise. On recognizing the doorbell sound, the bracelet will vibrate with the pattern associated with the sound in question which might be something like alternating between strong vibrations and pauses. The OLED display will also additionally show a house emoji to denote that the house doorbell is ringing.

# SOLUTION COMPONENTS

Based on this solution we have identified that we need the following components:

- INMP441 (Microphone Component)

- Brushed ERM (Vibration Motor)

- Powerboost 1000 (Power subsystem)

- 1000 mAh LiPo battery x 2 (hot swappable)

- SSD1306 (OLED display)

## SUBSYSTEM 1 → SOUND DETECTION SUBSYSTEM

This subsystem will consist of a microphone and will be responsible for picking up sounds from the environment and conducting a real-time FFT on them. After this, we will filter out lower frequencies and use a frequency-matching algorithm to infer if a pre-programmed sound was picked up by the microphone. This inference will be outputted to the main control unit in real-time.

## SUBSYSTEM 2 → VIBRATION SUBSYSTEM

This subsystem will be responsible for vibrating the bracelet on the wearer’s wrist. Using the vibration motor mentioned above, we should have a frequency range of 30Hz~500Hz, which should allow for the generation of a variety of distinguishable patterns. This subsystem will be responsible for the generation of the patterns and control of the motor, as well as prompting the Display subsystem to visualize the type of notification detected.

## SUBSYSTEM 3 → DISPLAY SUBSYSTEM

The Display subsystem will act as a set of visual cues in addition to the vibrations, as well as a visual feedback system for user interactions. This system should not draw a lot of power as it will be active only when prompted by user interaction or by a recognized sound. Both of these scenarios are relatively uncommon over the course of a day, which means that the average power draw for our device should still remain low.

## SUBSYSTEM 4 → USER INTERACTION SUBSYSTEM

This subsystem is responsible for the interaction of the user with the bracelet. This subsystem will include a set of buttons for tasks such as checking the charge left on the battery or turning off a notification. Checking the charge will also display the charge on the OLED display thus interacting and controlling the display subsystem as well.

## SUBSYSTEM 5 → POWER SUBSYSTEM

This subsystem is responsible for powering the device. One of our success criteria is that we want long battery life and low downtime. In order to achieve this we will be using a power boost circuit in conjunction with two rechargeable 1000 mAh batteries. While one is charging the other can be used so the user doesn’t have to go without the device for more than a few seconds at a time. We are expecting our device to use anywhere from 20-50mA which would mean we get an effective use time of more than a day. The power boost circuit and LiPo battery’s JST connector allow the user to secure and quick battery swaps as well.

# CRITERION FOR SUCCESS

- The bracelet should accurately identify only the crucial sounds in the wearer’s environment with each type of sound having a fixed unique vibration + LED pattern associated with it

- The vibration patterns should be distinctly recognizable by the wearer

- Should be relatively low cost

- Should have prolonged battery life (so the power should focus on only the use case of converting sound to vibration)

- Should have a small profile and a sleek form factor

Project Videos